Tzion_ben_Arthur

iTrader: (19)

First of all, I am an out-of-the-closet power glide man. I like power glides. I dont like to shift very often and I don't like heavy crap hanging off of my car. With that said, I found myself defending a th400 with a "non-sponsor" trans builder. I use to have a th400 that I drove in second and third for the most part. I loved the trans, but it really did not meet my turbo needs. The builder was telling me that the TH400 sucks 30% of the power from the motor and that the PG was only a fraction of that. I was like 30%

Well after doing a search, I noticed that there are people on both sides of the fence regarding this subject. I agree I have seen people pick up some et by going to a PG, but come on! Is it really true or is this dyno legend? Has anyone did a TH400 to PG test on the dyno and track? How about a 6speed to TH400 dyno test? I know most pick up ET when converting from 6-speed to auto, but how about measurable HP.

Please note that I am a straight line guy that drives his car to the coffee shop and burger joint. I measure success in ET and durability, but this 30% thing was very hard to swallow.

Tzion_ben_Arthur

iTrader: (19)

.... thats what I thought. It is pure BS. No real back to back evidence.

StreetSilverado

iTrader: (17)

I'd like to know this also. I went from a 4L65E to the TH400 and there IS a power loss between the two. Track times prove it.

I went from weighing 3,612lbs and a 4L65E it ran a 6.96 @ 97MPH

Now I weigh in at 3,448 and a TH400 and it's ran a 6.95 @101 MPH

Sometimes I wish I would have went powerglide...actually I still might. When the fluid is cold the car will run in the 7.05 range, then once it gets pretty hot it will drop to mid 6.95s.

built408

iTrader: (10)

I lost about 35-40 rwhp from a 6-speed to a 400. But alot of that loss is from a loose converter. Although I picked up .6 in 1/8th.

Predator T/A

iTrader: (7)

at the same power level going from a 60e to a 400 you will lose a bit of time not necesarily due to power consumption but the th400 has a considerably higher first gear ratio your going from a 3.059 first gear to a 2.48 first gear so at the same power level your short track times will be off remember the ET is made through the first 300 feet of the run if your slower off the line due to higher gears you will suffer in ET

leonpiper69

iTrader: (3)

i was just arguing this my buddy who just bought a six spd car (that i drove almost 1,000 miles to deliver for him!!). he was saying a 6 spd only loses 13% and and automatic loses 18-20%. i told him i thought it was more like 18-20 for stick cars and 25% for automatics.

w3s1c0a5t

iTrader: (3)

Its going to very huge on automatics.

And your friend is probably closer.

robbyredneck

iTrader: (1)

i don't know but i think i'd give up 80% of my horsepower if my car ran 8's. nice thread tzion